Ajax: How To Weave A Faster Web

Do a search on Google Maps for your house, and you'll see a nice enough map of your neighborhood. Now hold down the mouse button. You'll find you can move the map around as quickly as if it were sitting on a table. Zooming in and out, there's no delay waiting for the page to reload. And you can switch instantly to corresponding satellite photos and even a combined map-photo view.

Who would have thought poring over a map could be so fun? Credit a loose-knit set of programming technologies known as Ajax. It's helping to spur the explosion of Web sites, from Yahoo! Inc.'s (YHOO ) photo-sharing service Flickr to Google Inc.'s (GOOG ) Web-based e-mail service, that help you take a more active part in creating your own personal Web.

Essentially, Ajax speeds up the Web experience, vastly reducing the notorious World Wide Wait. A Web site created using Ajax updates pages behind the scenes, sending ancillary data you're likely to want next -- such as filling in map data surrounding the current view. No more clicking the mouse and waiting for the page to refresh. Says Jesse James Garrett, director of user experience at Web design consultant Adaptive Path, who coined the term Ajax: "Companies are really starting to recognize that the Web is more than a medium of static pages."

The upshot: For the first time, the Web has become a place for real applications that match -- and sometimes transcend -- the performance of desktop software. "Until Google put this technology out there, no one was really thinking of Web pages as applications," says Sapient Corp. (SAPE ) software architect Francis Shanahan. "In the next 12 months, people will be thinking about the Web in a new way."

Ajax has rough edges. The programming tools behind it are still primitive, so writing software with it takes longer. And sometimes the resulting software flouts Web browser customs -- for instance, disabling the "back" button. But already, Ajax is finding its way into mainstream business applications such as Sabre Holdings Corp.'s (TSG ) air scheduling software.

Future possibilities are intriguing, too. Even with Amazon's patented "one-click" buying, you have to click on multiple pages to view a book, read reviews, get to the checkout page and shopping cart. Garrett suggests Ajax might allow all that to be done on one page. It doesn't get any speedier than that.

By Robert D. Hof in San Mateo, Calif.

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